Full-reception light path of small-aperture single-atom filter of resonance fluorescence laser radar

Abstract

A full-reception light path of a small-aperture single-atom filter of a resonance fluorescence laser radar and a detection method, applied to the technical field of laser radars. The full-reception light path comprises: a front light path assembly (100) used for collimating and converging a light beam and decomposing the light beam into a first light beam and a second light beam, wherein the polarization directions of the first light beam and the second light beam are perpendicular to each other, the divergence angle of the collimated light beam is smaller than a first preset angle, the divergence angle of the converged light beam is smaller than a second preset angle, and the first preset angle is smaller than the second preset angle; a polarized light path assembly (200), comprising a first light path assembly (210) and a second light path assembly (220), which are respectively used for transmitting the first light beam and the second light beam to a rear light path assembly (300) so as to filter out noise light in the first light beam; and the rear light path assembly (300) used for simultaneously detecting the first light beam and the second light beam after the noise light has been filtered out.

Description

Full-receiving optical path of small-aperture single-atom filter for resonant fluorescence lidar Technical Field

[0001] The present disclosure relates to the field of laser radar technology, and more specifically to a resonant fluorescence laser radar small-aperture single-atom filter full-receiving optical path and detection method. Background Art

[0002] Resonance fluorescence lidar (RFL) is a powerful tool for detecting atmospheric parameters at altitudes of 80-105 kilometers in the mesosphere and lower thermosphere with high temporal and spatial resolution, such as atmospheric temperature, wind speed, and atomic density. Currently, a variety of RFLs utilizing different atoms are available internationally, including sodium, potassium, and iron. For sodium RFL, since the resonant fluorescence excitation wavelength of sodium atoms is the visible light wavelength of 589.159 nm, suppressing daytime background noise is particularly important for detecting high-altitude signals during daylight hours.

[0003] Atomic filters, with their narrow linewidth and high out-of-band suppression ratio, have been successfully applied to daytime detection by sodium and potassium warm wind lidars. However, due to the atmospheric depolarization of the echo signal, the echo signal received by the lidar telescope contains both S- and P-polarization components. Existing sodium and potassium warm wind lidar systems only receive the echo of a single polarization component, resulting in the loss of nearly half of the echo signal, significantly affecting the system's detection efficiency. Related technologies use dual-channel independent atomic filters to receive the echo signal, achieving full reception of the echo signal.

[0004] In the process of realizing the concept of the present disclosure, the inventors found that there are at least the following problems in the related technology: the use of a dual-channel independent atomic filter to receive the echo signal requires separate magnetic field, insulation and temperature control, and it is difficult to ensure complete consistency in technical implementation; moreover, the dual-channel independent atomic filter occupies a large volume and has a high implementation cost.

[0005] Summary of the Invention

[0006] In view of the above problems, the present disclosure provides a resonant fluorescence lidar small-aperture single-atom filter full-receiving optical path and a detection method.

[0007] According to the first aspect of the present disclosure, a resonant fluorescence laser radar small-aperture single-atom filter full-receiving optical path is provided, comprising: a front optical path component, for collimating and converging a light beam, and decomposing the light beam into a first light beam and a second light beam, wherein the polarization directions of the first light beam and the second light beam are perpendicular to each other, the divergence angle of the collimated light beam is less than a first preset angle, and the divergence angle of the converged light beam is less than a second preset angle, and the first preset angle is less than the second preset angle; a polarization optical path component, comprising a first optical path component and a second optical path component, the first optical path component being used to transmit the first light beam to a rear optical path component, wherein the first optical path formed by the first optical path component passes through an atom pool to filter out noise light in the first light beam; the second optical path component being used to transmit the second light beam to the rear optical path component, wherein the second optical path formed by the second optical path component passes through the atom pool to filter out noise light in the second light beam; and the rear optical path component being used to simultaneously detect the first light beam and the second light beam after filtering out the noise light.

[0008] According to an embodiment of the present disclosure, when the above-mentioned first light beam enters the above-mentioned atomic pool, the divergence angle of the above-mentioned first light beam is less than the third preset angle; when the above-mentioned second light beam enters the above-mentioned atomic pool, the divergence angle of the above-mentioned second light beam is less than the above-mentioned third preset angle, and the above-mentioned third preset angle is greater than the above-mentioned second preset angle.

[0009] According to an embodiment of the present disclosure, the above-mentioned first optical path component and the above-mentioned second optical path component are distributed on the upper and lower sides of the central axis of the small-aperture single-atom filter full-receiving optical path of the above-mentioned resonant fluorescence laser radar, and the optical axis of the first optical path formed by the above-mentioned first optical path component does not intersect with the optical axis of the second optical path formed by the above-mentioned second optical path component; the distance between the component edge of the above-mentioned first optical path component away from the above-mentioned central axis and the component edge of the above-mentioned second optical path component away from the above-mentioned central axis is less than 22 mm.

[0010] According to an embodiment of the present disclosure, the first light beam and the second light beam are controlled according to the same control parameters at the atom cell.

[0011] According to an embodiment of the present disclosure, the detection assembly includes: the optical path of the first optical path is equal to the optical path of the second optical path, so that the first light beam and the second light beam reach the rear optical path assembly at the same time.

[0012] According to an embodiment of the present disclosure, the above-mentioned rear optical path component includes: a first polarization splitter, used to merge the above-mentioned first light beam after filtering out noise light and the above-mentioned second light beam into a third light beam; a focusing lens group, used to converge the above-mentioned third light beam into a fourth light beam; a detector, arranged after the above-mentioned focusing lens group, used to detect the above-mentioned fourth light beam; wherein the above-mentioned focusing lens group is used to converge the pupil imaging of the above-mentioned fourth light beam to the photosensitive detection surface of the above-mentioned detector; the width of the above-mentioned photosensitive detection surface is smaller than the width of the above-mentioned focusing lens group.

[0013] According to an embodiment of the present disclosure, the above-mentioned front optical path component includes: an optical fiber for receiving the above-mentioned light beam; a fiber optic collimator group, arranged after the above-mentioned optical fiber, for collimating the above-mentioned light beam output by the above-mentioned optical fiber, wherein the divergence angle of the light beam output by the above-mentioned fiber optic collimator group is less than a fourth preset angle, and the above-mentioned fourth preset angle is greater than the above-mentioned first preset angle and less than the above-mentioned second preset angle; a first focusing lens, arranged after the above-mentioned fiber optic collimator group, for converging the collimated light beam to obtain a converged light beam, wherein the divergence angle of the light beam output by the first focusing lens is less than the second preset angle; a second polarization splitter, arranged after the above-mentioned first focusing lens, for decomposing the above-mentioned light beam into the above-mentioned first light beam and the above-mentioned second light beam.

[0014] According to an embodiment of the present disclosure, the above-mentioned first optical path component includes: a first reflector, used to change the direction of the above-mentioned first light beam; a second focusing lens, arranged after the above-mentioned first reflector, used to image the optical fiber end face of the above-mentioned first light beam to a first position; a third focusing lens, arranged between the above-mentioned second focusing lens and the above-mentioned atomic pool, and the above-mentioned third focusing lens serves as a field lens, used to input the above-mentioned first light beam into the above-mentioned atomic pool; wherein the above-mentioned first position is located between the above-mentioned second focusing lens and the above-mentioned third focusing lens; a fourth focusing lens, arranged after the above-mentioned atomic pool, used to converge the above-mentioned first light beam output from the above-mentioned atomic pool; a fifth focusing lens, arranged after the above-mentioned fourth focusing lens, used to converge the above-mentioned optical fiber end face into an image; wherein the above-mentioned second focusing lens and the above-mentioned third focusing lens are used together to image the pupil of the above-mentioned first light beam to a second position, and the above-mentioned second position is located between the above-mentioned atomic pool and the above-mentioned fifth focusing lens.

[0015] According to an embodiment of the present disclosure, the above-mentioned second optical path component includes: a sixth focusing lens, used to image the optical fiber end face of the above-mentioned second light beam to a third position; a seventh focusing lens, arranged between the above-mentioned sixth focusing lens and the above-mentioned atomic pool, and the above-mentioned seventh focusing lens serves as a field lens, used to input the above-mentioned second light beam into the above-mentioned atomic pool; wherein the above-mentioned third position is located between the above-mentioned seventh focusing lens and the above-mentioned atomic pool; an eighth focusing lens, used to converge the second light beam output from the above-mentioned resonant fluorescence laser radar small-aperture single atom filter; a ninth focusing lens, arranged after the above-mentioned eighth focusing lens, used to converge the above-mentioned optical fiber end face to form an image; wherein the above-mentioned sixth focusing lens and the above-mentioned seventh focusing lens are used together to image the pupil of the above-mentioned second light beam to a fourth position, and the above-mentioned fourth position is located between the above-mentioned atomic pool and the above-mentioned ninth focusing lens; a second reflector, arranged after the above-mentioned ninth focusing lens, used to reflect the above-mentioned second light beam collimated by the above-mentioned ninth focusing lens to the above-mentioned rear optical path component.

[0016] The second aspect of the present disclosure provides a detection method, including: receiving and converging a light beam through a front optical path component, and decomposing the light beam into a first light beam and a second light beam, wherein the polarization directions of the first light beam and the second light beam are perpendicular to each other; transmitting the first light beam to a rear optical path component through a first optical path component in the polarization light path component, wherein the first light path formed by the first light path component passes through an atom pool to filter out noise light in the first light beam; transmitting the second light beam to a rear optical path component through a second optical path component in the polarization light path component, wherein the second light path formed by the second optical path component passes through the atom pool to filter out noise light in the second light beam; and simultaneously detecting the first light beam and the second light beam after filtering out the noise light through the rear optical path component.

[0017] According to the embodiments of the present disclosure, the resonant fluorescence lidar small-aperture single-atom filter full-receiving optical path decomposes the echo signal light received by the resonant fluorescence lidar into a first light beam and a second light beam with mutually perpendicular polarization directions. After separation, the two light beams enter the first light path and the second light path respectively. The light beams of the two light paths pass through the atom pool at the same time, and finally merge into a single light beam to reach the detector photosensitive surface, realizing miniaturized and compact light beam transmission. In addition, because the light beams of the two light paths pass through the atom pool at the same time, the atom pool can achieve the operation of simultaneous insulation and temperature control of two light beams with different polarization directions, thereby ensuring the consistency of control parameters and data. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above contents and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0019] FIG1 shows a structural diagram of a full-receiving optical path of a small-aperture single-atom filter for a resonant fluorescence lidar according to an embodiment of the present disclosure.

[0020] FIG2 shows an optical structure diagram of a full-receiving optical path of a small-aperture single-atom filter for a resonant fluorescence lidar according to an embodiment of the present disclosure.

[0021] FIG3 shows a structural diagram of an atom pool according to an embodiment of the present disclosure.

[0022] FIG4 shows an optical path diagram of the first optical path of the full-receiving optical path of the small-aperture single-atom filter of the resonant fluorescence lidar according to an embodiment of the present disclosure.

[0023] FIG5 shows an optical path diagram of the second optical path of the resonant fluorescence lidar small-aperture single-atom filter full-receiving optical path according to an embodiment of the present disclosure.

[0024] FIG6 shows a combined optical path diagram of the first optical path and the second optical path of the full-receiving optical path of the small-aperture single-atom filter of the resonant fluorescence laser radar according to an embodiment of the present disclosure.

[0025] FIG7 shows a combined structural diagram of the first optical path and the second optical path of the full-receiving optical path of the small-aperture single-atom filter of the resonant fluorescence lidar according to an embodiment of the present disclosure.

[0026] FIG8 shows a structural diagram of a polarization beam splitter prism according to an embodiment of the present disclosure.

[0027] FIG. 9 illustrates a front view of a rectangular prism according to an embodiment of the present disclosure.

[0028] FIG. 10 illustrates a side view of a rectangular prism according to an embodiment of the present disclosure.

[0029] FIG11 shows a detection method using a resonant fluorescence lidar small-aperture single-atom filter full-receiving optical path according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0030] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0031] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise," "include," etc. used herein indicate the presence of the features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0032] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0033] When expressions such as "at least one of A, B and C, etc." are used, they should generally be interpreted in accordance with the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0034] An embodiment of the present disclosure provides a resonant fluorescence laser radar small-aperture single-atom filter full-receiving optical path, a front optical path component, used to receive and converge a light beam, and decompose the light beam into a first light beam and a second light beam, wherein the polarization directions of the first light beam and the second light beam are perpendicular to each other, the divergence angle of the collimated light beam is less than a first preset angle, and the divergence angle of the converged light beam is less than a second preset angle, and the first preset angle is less than the second preset angle; a polarization optical path component, including a first optical path component and a second optical path component, the first optical path component is used to transmit the first light beam to a rear optical path component, wherein the first optical path formed by the first optical path component passes through an atom pool to filter out noise light in the first light beam; the second optical path component is used to transmit the second light beam to the rear optical path component, wherein the second optical path formed by the second optical path component passes through the atom pool to filter out noise light in the second light beam; the rear optical path component is used to simultaneously detect the first light beam and the second light beam after filtering out the noise light.

[0035] FIG1 schematically shows a structural diagram of a full-receiving optical path of a small-aperture single-atom filter for a resonant fluorescence lidar according to an embodiment of the present disclosure.

[0036] As shown in FIG1 , the resonant fluorescence lidar small-aperture single-atom filter full-receiving optical path can be composed of a front optical path component 100 , a polarization optical path component 200 , and a rear optical path component 300 . The polarization optical path component includes a first optical path component 210 and a second optical path component 220 .

[0037] According to the embodiments of the present disclosure, the full-receiving optical path of the small-aperture single-atom filter of the resonant fluorescence lidar can be understood as the implementation optical path of the small-aperture single-atom filter of the resonant fluorescence lidar.

[0038] According to an embodiment of the present disclosure, the front optical path component 100 is used to receive a light beam from outside the full-receiving optical path of the small-aperture single-atom filter of the resonant fluorescence lidar, and to converge the light beam and decompose it into a first light beam and a second light beam with polarization directions perpendicular to each other.

[0039] According to an embodiment of the present disclosure, the divergence angle of the collimated light beam is less than a first preset angle, and the divergence angle of the converged light beam is less than a second preset angle, and the first preset angle is less than the second preset angle. For example, the first preset angle is 4.5° and the second preset angle is 8°.

[0040] According to an embodiment of the present disclosure, the polarization optical path component 200 is placed after the front optical path component 100 and includes a first optical path component 210 and a second optical path component 220. The first optical path component 210 can transmit the first light beam to the atomic cell to filter out noise light, and then transmit the first light beam after filtering out noise light to the rear optical path component 300. The second optical path component 220 can be used to transmit the second light beam to the atomic cell to filter out noise light, and then transmit the second light beam after filtering out noise light to the rear optical path component 300.

[0041] According to an embodiment of the present disclosure, the post-optical path component 300 is placed after the polarization optical path component 200 and is used to simultaneously detect the first light beam and the second light beam after the noise light is filtered out.

[0042] According to an embodiment of the present disclosure, the pre-optical path assembly 100 may include optical components such as an optical fiber and a collimator. The optical fiber is used to receive a light beam from outside the resonant fluorescence lidar's small-aperture single-atom filter's full-receive optical path. The collimator is used to collimate the received light beam into a beam with a smaller emission angle. The light beam may be a light beam that needs to be detected, such as an echo signal.

[0043] According to an embodiment of the present disclosure, the front optical path assembly 100 may further include an optical element such as a polarization beam splitter prism. The polarization beam splitter prism may be made of optical glass, such as fused quartz, K9, or BK7, or an optical resin, such as PMMA or PC. The polarization beam splitter prism is used to split a light beam into a first light beam and a second light beam, which are perpendicular to each other.

[0044] According to an embodiment of the present disclosure, the polarization optical path component 200 may include optical elements such as a reflector, a focusing lens, etc. The reflector may be used to change the transmission direction of the light beam, and the focusing lens may be used to transmit the light beam.

[0045] According to an embodiment of the present disclosure, the first optical path component 210 may include optical components such as a focusing lens and a reflector. The reflector can be used to change the transmission direction of the first light beam, and the focusing lens can be used to transmit the first light beam to the atom pool and can also be used to transmit the first light beam after filtering out noise waves to the post-optical path component 300.

[0046] According to an embodiment of the present disclosure, the second optical path component 220 may include optical components such as a focusing lens and a reflector. The focusing lens can be used to transmit the second light beam to the atom cell and can also be used to transmit the second light beam after noise light is filtered out to the reflector. The reflector can be used to reflect the second light beam after noise light is filtered out to the post-optical path component 300.

[0047] According to an embodiment of the present disclosure, the rear optical path assembly 300 may include optical components such as a polarization beam splitter prism and a detector. The polarization beam splitter prism may be made of optical glass, such as fused quartz, K9, or BK7, or optical resin, such as PMMA or PC. The polarization beam splitter prism may be used to reflect the first light beam, after filtering out noise light, to the detection assembly, and transmit the second light beam, after filtering out noise light, to the detector. The detector may be used to detect the light beam.

[0048] The atomic pool in the embodiment of the present disclosure can be a single atom pool such as a sodium atom pool, a potassium atom pool, etc., to form a full-receiving optical path of a small-aperture single atom filter of a resonant fluorescence lidar.

[0049] According to the embodiments of the present disclosure, the resonant fluorescence lidar small-aperture single-atom filter full-receiving optical path decomposes the echo signal light received by the resonant fluorescence lidar into a first light beam and a second light beam with mutually perpendicular polarization directions. After separation, the two light beams enter the first light path and the second light path respectively. The light beams of the two light paths pass through the atom pool at the same time, and finally merge into a single light beam to reach the detector photosensitive surface, realizing compact light beam transmission. In addition, because the light beams of the two light paths pass through the atom pool at the same time, the atom pool can achieve the simultaneous insulation and temperature control of the two light beams with different polarization directions, thereby ensuring data consistency.

[0050] According to an embodiment of the present disclosure, the divergence angle of the first light beam can be the maximum deviation angle between the first light beam and the optical axis. The divergence angle of the second light beam can be the maximum deviation angle between the second light beam and the optical axis. The third preset angle can be 9°, and the divergence angles of the first light beam and the second light beam are both less than the third preset angle, that is, the divergence angles of the first light beam and the second light beam are both less than 9°.

[0051] According to an embodiment of the present disclosure, the first optical path component and the second optical path component are respectively distributed on the upper and lower sides of the central axis of the full-receiving optical path of the small-aperture single-atom filter of the resonant fluorescence lidar, and the optical axis of the first optical path formed by the first optical path component does not intersect with the optical axis of the second optical path formed by the second optical path component; wherein, the first light beam and the second light beam pass through the atomic pool at the same time.

[0052] For example, the optical axis of the first optical path and the optical axis of the second optical path are approximately parallel.

[0053] According to an embodiment of the present disclosure, the distance between the edge of the first optical path component away from the central axis and the edge of the second optical path component away from the central axis is less than 22 mm, that is, the height / width of the entire resonant fluorescence lidar small-aperture single-atom filter full-receiving optical path is less than 22 mm.

[0054] In an embodiment of the present disclosure, the overall width / height of the optical components forming the full-receiving optical path is less than 22 mm. When the above-mentioned full-receiving optical path is applied to a single-atom filter, the width / height of the external mechanical structure of the single-atom filter is less than or equal to 25 mm, that is, a small-aperture single-atom filter is formed.

[0055] According to an embodiment of the present disclosure, the optical path of the first optical path is equal to the optical path of the second optical path. Specifically, the optical path of the first light beam output by the front optical path component and then transmitted via the second optical path to the rear optical path component is equal to the optical path of the second light beam output by the front optical path component and then transmitted via the second optical path to the rear optical path component. The first light beam and the second light beam are simultaneously output by the front optical path component and arrive at the rear optical path component at the same time.

[0056] According to an embodiment of the present disclosure, the atom cell is used to control the first light beam and the second light beam according to the same control parameters.

[0057] According to an embodiment of the present disclosure, a heat-insulating shell, a magnet kit, and a temperature control kit are provided outside the atomic pool, thereby enabling the temperature and magnetic field to be controlled at the atomic pool.

[0058] According to an embodiment of the present disclosure, one of the first light beam and the second light beam is an S-polarized light component, and the other is a P-polarized light component.

[0059] In the embodiments of the present disclosure, the fully receiving optical path can use a single set of magnets to achieve magnetic rotation, and the magnetic field control effect on the S-polarized and P-polarized components of light is the same, ensuring good consistency; the fully receiving optical path can also use the same temperature control device, such as an insulation layer, and the effect of temperature on the S-polarized and P-polarized components of light is exactly the same.

[0060] Therefore, the full-receiving optical path of the small-aperture single-atom filter of the resonant fluorescence lidar in the embodiment of the present disclosure can realize the simultaneous detection of S polarization and P polarization while ensuring a small occupied volume and using fewer devices, thereby greatly reducing the cost of the small-aperture single-atom filter of the resonant fluorescence lidar.

[0061] According to an embodiment of the present disclosure, the rear optical path component includes: a first polarization splitter, used to merge the first light beam and the second light beam after filtering out the noise light into a third light beam; a focusing lens group, used to converge the third light beam into a fourth light beam; and a detector, arranged after the focusing lens group, used to detect the fourth light beam.

[0062] According to an embodiment of the present disclosure, the first polarization beam splitter may include a polarization beam splitting prism, the focusing lens group may include a biconvex lens, and the detector may include a photosensitive detection surface for receiving the light beam signal, wherein the width of the photosensitive detection surface is smaller than the width of the focusing lens group.

[0063] According to an embodiment of the present disclosure, the focusing lens group is used to converge the pupil imaging of the fourth light beam to the photosensitive detection surface of the detector, and the detector receives the pupil imaging of the fourth light beam and detects the fourth light beam.

[0064] According to an embodiment of the present disclosure, an optical fiber is used to receive a light beam; a fiber optic collimator group is arranged after the optical fiber and is used to collimate the light beam output by the optical fiber; a first focusing lens is arranged after the fiber optic collimator group and is used to converge the collimated light beam to obtain a converged light beam; a second polarization splitter is arranged after the first focusing lens and is used to decompose the light beam into a first light beam and a second light beam.

[0065] According to an embodiment of the present disclosure, a front optical path assembly may include an optical fiber, a fiber collimator assembly, a first focusing lens, and a second polarization beam splitter. The divergence angle of the light beam output by the fiber collimator assembly is less than a first preset angle, and the divergence angle of the light beam output by the first focusing lens is less than a second preset angle.

[0066] According to an embodiment of the present disclosure, the optical fiber collimator assembly may include a meniscus lens and a biconvex lens, the first focusing lens may be a relay lens, and the second polarization beam splitter may be a polarization beam splitter prism. The second polarization beam splitter prism may be the same as or different from the first polarization beam splitter prism.

[0067] According to an embodiment of the present disclosure, the divergence angle of the light beam output by the optical fiber collimating lens assembly is less than 4.5°.

[0068] According to an embodiment of the present disclosure, the first optical path component includes: a first reflector, used to change the direction of the first light beam; a second focusing lens, arranged after the first reflector, used to image the optical fiber end face of the first light beam to a first position; a third focusing lens, arranged between the second focusing lens and the atomic pool, the third focusing lens serving as a field lens, used to input the first light beam into the atomic pool; a fourth focusing lens, arranged after the atomic pool, used to converge the first light beam output from the atomic pool; a fifth focusing lens, arranged after the fourth focusing lens, used to converge the optical fiber end face to form an image.

[0069] According to an embodiment of the present disclosure, the first optical path component may include a first reflecting mirror, a second focusing lens, a third focusing lens, a fourth focusing lens, and a fifth focusing lens.

[0070] According to an embodiment of the present disclosure, the first position is between the second focusing lens and the third focusing lens.

[0071] According to an embodiment of the present disclosure, the second focusing lens and the third focusing lens are used together to image the pupil of the first light beam to a second position, and the second position is located between the atom pool and the fifth focusing lens. For example, the second position can be located near the fourth focusing lens.

[0072] According to an embodiment of the present disclosure, the second optical path component includes: a sixth focusing lens, used to image the optical fiber end face of the second light beam to a third position; a seventh focusing lens, arranged between the sixth focusing lens and the atomic pool, and the seventh focusing lens serves as a field lens, used to input the second light beam into the atomic pool; an eighth focusing lens, used to converge the second light beam output from the resonant fluorescence lidar single atom filter; a ninth focusing lens, arranged after the eighth focusing lens, used to converge the optical fiber end face into an image; a second reflector, arranged after the ninth focusing lens, used to reflect the second light beam collimated by the ninth focusing lens to the rear optical path component.

[0073] According to an embodiment of the present disclosure, the second optical path component may include a sixth focusing lens, a seventh focusing lens, an eighth focusing lens, a ninth focusing lens and a second reflecting mirror.

[0074] According to an embodiment of the present disclosure, the third position is located between the seventh focusing lens and the atom cell.

[0075] According to an embodiment of the present disclosure, the sixth focusing lens and the seventh focusing lens are used together to image the pupil of the second light beam to a fourth position, which is located between the atom pool and the ninth focusing lens. For example, the fourth position can be located near the eighth focusing lens.

[0076] FIG. 2 schematically shows an optical structure diagram of a full receiving optical path of a small-aperture single-atom filter for a resonance fluorescence lidar according to an embodiment of the present disclosure.

[0077] As shown in FIG. 2, the optical structure of the full receiving optical path of the small-aperture single-atom filter for the resonance fluorescence lidar may include an optical fiber 1, an optical fiber collimating lens group 2, a filter 3, a focusing lens 4, a polarization beam splitter prism 5, an upper optical path 6, a lower optical path 7, a polarization beam splitter prism 8, a focusing lens group 9, a detector photosensitive surface 1001, and a small-aperture single-atom filter absorption cell 1002 of the resonance fluorescence lidar.

[0078] According to an embodiment of the present disclosure, the optical fiber 1 is used to introduce external light into the full receiving optical path of the small-aperture single-atom filter for the resonance fluorescence lidar. The optical fiber 1 may be a single optical fiber or an optical fiber bundle integrated by multiple optical fibers. The numerical aperture NA of the optical fiber 1 satisfies 0.12 ≤ NA ≤ 0.64.

[0079] According to an embodiment of the present disclosure, the optical fiber collimating lens group 2 is composed of a meniscus lens and a biconvex lens. The meniscus lens is composed of two spherical surfaces or aspherical surfaces, and the biconvex lens is composed of two biconvex spherical surfaces or convex aspherical surfaces. As shown in FIG. 2, the meniscus lens includes a front surface concave surface 211 and a rear surface concave surface 212, and the biconvex lens includes a front convex spherical surface 221 and a rear convex spherical surface 222.

[0080] According to an embodiment of the present disclosure, the materials of the meniscus lens and the biconvex lens may be optical glass, such as fused quartz, aluminum oxide, K9, BK7, ZF2, etc., or resin materials, such as PMMA, PC, etc.

[0081] According to an embodiment of the present disclosure, the optical fiber collimating lens group 2 is used to collimate the beam output from the optical fiber 1 into a beam with a small divergence angle. The divergence angle a2 of the beam collimated by the optical fiber collimating lens group is less than 4.5°. The focal length fa2 of the optical fiber collimating lens group 2 satisfies 5 mm < fa2 < 15 mm.

[0082] According to an embodiment of the present disclosure, the filter 3 is used to pass a beam within a specific wavelength range, and the wavelength of the passed beam may be any value within the range of 2000 nm to 3000 nm. The filter 3 may be circular or square, preferably circular. When the filter 3 is circular, the diameter D3 of the filter 3 satisfies 10 mm ≤ D3 ≤ 15 mm, and the thickness t3 satisfies 0.5 mm < t3 < 5 mm. The front surface 31 and the rear surface 32 of the filter 3 are flat surfaces.

[0083] According to an embodiment of the present disclosure, focusing lens 4 is a relay lens. Its front and rear surfaces cannot both be concave. Instead, it can be biconvex, have one flat surface and the other convex, or have one concave surface and the other convex. For example, both the front surface 41 and the rear surface 42 of focusing lens 4 can be convex. The focal length fa4 of focusing lens 4 satisfies the condition 50 mm < fa4 < 110 mm.

[0084] According to an embodiment of the present disclosure, the material of the focusing lens 4 can be optical glass, such as fused quartz, aluminum oxide, K9, BK7, ZF2, etc., or can be resin material, such as PMMA, PC, etc.

[0085] According to an embodiment of the present disclosure, the material of the polarization beam splitter prism 5 and the polarization beam splitter prism 8 can be optical glass, such as fused quartz, K9, B87, etc., or optical resin, such as PMMA, PC, etc. The polarization beam splitter prism 5 and the polarization beam splitter prism 8 are used to decompose the light beam into P-polarized light and S-polarized light with polarization directions perpendicular to each other. It can be that the S-polarized light is transmitted and the P-polarized light is reflected, or the S-polarized light is reflected and the P-polarized light is transmitted. For example, the first surface 51, the second surface 52 and the third surface 53 of the polarization beam splitter prism 5 are all planes, and the first surface 81, the second surface 82 and the third surface 83 of the polarization beam splitter prism 8 are all planes, and the oblique surfaces of the polarization beam splitter prism 5 and the polarization beam splitter prism 8 are coated with a polarization beam splitting film.

[0086] According to an embodiment of the present disclosure, the sizes of the polarization beam splitter prism 8 and the polarization beam splitter prism 5 may be the same or different.

[0087] According to an embodiment of the present disclosure, the upper optical path 6 includes a plane reflection mirror 61 , a focusing lens 62 , a focusing lens 63 , a focusing lens 64 , and a focusing lens 65 .

[0088] According to an embodiment of the present disclosure, the surface 611 of the plane reflector 61 that contacts the first light beam is a plane. The plane reflector 61 can be a plane reflector or a right-angle prism.

[0089] According to an embodiment of the present disclosure, the focusing lens 62 can also be used to converge the first light beam again. Its function works together with the first focusing lens 4 to image the fiber end face of the first light beam to a first position near the focusing lens 63. The front and back surfaces of the focusing lens 62 cannot both be concave, but can both be convex. Alternatively, one surface can be flat and the other convex, or one surface can be concave and the other convex. For example, the front surface 621 and the back surface 622 of the focusing lens 62 are both convex.

[0090] According to an embodiment of the present disclosure, the focusing lens 63 can also work together with the focusing lens 62 to image the pupil of the first light beam near the focusing lens 64. The front and rear surfaces of the focusing lens 63 cannot both be concave, but can both be convex. Alternatively, one surface can be flat and the other convex, or one surface can be concave and the other convex. For example, the front surface 631 and the rear surface 632 of the focusing lens 63 are both convex, and the front surface 641 and the rear surface 642 of the focusing lens 64 are both convex.

[0091] According to an embodiment of the present disclosure, the front and rear surfaces of the focusing lens 65 cannot both be concave, but can both be convex, or one surface can be flat and the other convex, or one surface can be concave and the other convex. For example, the front surface 651 and the rear surface 652 of the focusing lens 65 are both convex.

[0092] According to an embodiment of the present disclosure, the focusing lens 62 , the focusing lens 63 , the focusing lens 64 and the focusing lens 65 may be made of optical glass materials, such as fused quartz or aluminum oxide.

[0093] According to an embodiment of the present disclosure, the focal length f62 of the focusing lens 62 satisfies 50 mm < f62 < 110 mm. The focal length f63 of the focusing lens 63 satisfies 15 mm < f63 < 45 mm. The focal length f64 of the focusing lens 64 satisfies 15 mm < f64 < 45 mm. The focal length f65 of the focusing lens 65 satisfies 20 mm < f65 < 55 mm.

[0094] According to an embodiment of the present disclosure, the lower optical path 7 includes a focusing lens 71 , a focusing lens 72 , a focusing lens 73 , a focusing lens 74 and a plane reflection mirror 75 .

[0095] According to an embodiment of the present disclosure, the surface 751 of the plane reflector 75 that contacts the second light beam is a plane. The plane reflector 75 can be a plane reflector or a right-angle prism.

[0096] According to an embodiment of the present disclosure, the focusing lens 71 , the focusing lens 72 , the focusing lens 73 and the focusing lens 74 may be made of optical glass materials, such as fused quartz or aluminum oxide.

[0097] According to an embodiment of the present disclosure, the focusing lens 71 is similar to the focusing lens 61, the focusing lens 72 is similar to the focusing lens 62, the focusing lens 73 is similar to the focusing lens 62, and the focusing lens 74 is similar to the focusing lens 64. For example, the front surface 711 and the rear surface 712 of the focusing lens 71 are both convex surfaces, the front surface 721 and the rear surface 722 of the focusing lens 72 are both convex surfaces, the front surface 731 and the rear surface 732 of the focusing lens 73 are both convex surfaces, and the front surface 741 and the rear surface 742 of the focusing lens 74 are both convex surfaces.

[0098] According to an embodiment of the present disclosure, the focal length f71 of the focusing lens 71 satisfies 50 mm < f71 < 110 mm. The focal length f72 of the focusing lens 72 satisfies 15 mm < f72 < 45 mm. The focal length f73 of the focusing lens 73 satisfies 15 mm < f73 < 45 mm. The focal length f74 of the focusing lens 74 satisfies 20 mm < f74 < 55 mm.

[0099] According to an embodiment of the present disclosure, the focusing lens group 9 is composed of a biconvex lens 91 and a biconvex lens 92. The biconvex lens 91 is composed of two spherical or aspherical surfaces, and the front surface 911 and the rear surface 912 are both convex surfaces. The biconvex lens 92 is composed of two convex spherical surfaces or convex aspherical surfaces. For example, the front surface 921 and the rear surface 922 of the biconvex lens 92 are both convex surfaces. The focal length f9 of the biconvex lens 91 and the biconvex lens 92 meets 5mm. <f9<20mm。

[0100] According to an embodiment of the present disclosure, the material of the biconvex lens 91 and the biconvex lens 92 can be optical glass, such as fused quartz, alumina, K9, BK7, ZF2, etc., or a resin material, such as PMMA, PC, etc.

[0101] According to an embodiment of the present disclosure, the diameters Dt of focusing lens 4 , focusing lens 62 , focusing lens 63 , focusing lens 64 , focusing lens 65 , focusing lens 71 , focusing lens 72 , focusing lens 73 , focusing lens 74 , biconvex lens 91 and biconvex lens 92 satisfy 8 mm < Dt ≤ 11 mm.

[0102] According to an embodiment of the present disclosure, the photosensitive detection surface 1001 is used to receive the fourth light beam. The photosensitive surface size S of the photosensitive detection surface 1001 satisfies 0mm<S≤8mm.

[0103] It should be noted that the first and second light beams of the full-receive optical path of the present application pass through the atomic pool through two channels reserved in the atomic pool. Each channel of the atomic pool is composed of parallel flat glass arranged at the entrance end, parallel flat glass arranged at the output end, and a hollow atomic pool cylinder.

[0104] FIG3 schematically shows a structural diagram of an atom pool according to an embodiment of the present disclosure.

[0105] According to an embodiment of the present disclosure, FIG3 schematically illustrates the structure of the portion of the atomic cell associated with the full-receiving optical path. The atomic cell may include parallel plate glass 001, parallel plate glass 002, and an atomic cell cylinder 003. It should be noted that the portion of the atomic cell located outside the full-receiving optical path may also include a heat-insulating housing, a magnet assembly, and a temperature control assembly.

[0106] According to embodiments of the present disclosure, parallel plate glass 001 and parallel plate glass 002 can be made of the same material, such as optical glass materials such as fused quartz, aluminum oxide, and Prex. Atom cell cylinder 003 can be a hollow cylinder made of glass materials such as Prex or quartz, filled with high-purity atoms. The front surface 0011 and rear surface 0012 of parallel plate glass 001, and the front surface 0021 and rear surface 0022 of parallel plate glass 002, are all flat surfaces.

[0107] According to an embodiment of the present disclosure, the diameter D001 of parallel flat glass 001 satisfies 20 mm ≤ D001 ≤ 23 mm. The diameter D002 of parallel flat glass 002 satisfies 20 mm ≤ D002 ≤ 23 mm. The distance d12 between parallel flat glass 001 and parallel flat glass 002 satisfies 20 mm ≤ 30 mm. The inner diameter D0031 of atom cell cylinder 003 satisfies 19 mm ≤ D0031 ≤ 23 mm. The outer diameter D0032 of atom cell cylinder 003 satisfies 24 mm ≤ D0032 ≤ 25 mm, preferably 25 mm.

[0108] According to an embodiment of the present disclosure, surfaces 0011 , 0012 , 0021 , and 0022 of the parallel plate glass 001 and the parallel plate glass 002 are all planes.

[0109] FIG4 schematically shows an optical path diagram of the first optical path of the full-receiving optical path of the small-aperture single-atom filter of the resonant fluorescence lidar according to an embodiment of the present disclosure.

[0110] As shown in Figure 4, the first optical path can include a fiber collimating lens group 2, a filter 3, a focusing lens 4, a polarization beam splitter prism 5, a plane reflector 61, a focusing lens 62, a focusing lens 63, a focusing lens 64, a focusing lens 65, a polarization beam splitter prism 8, a focusing lens group 9 and a detector photosensitive surface 1001.

[0111] According to an embodiment of the present disclosure, the layout of the first optical path is a Z-shaped layout.

[0112] According to an embodiment of the present disclosure, the first position af21 is located near the focusing lens 63. The second position af22 is located near the focusing lens 64. The first position may be an imaging plane of the optical fiber end face, and the second position may be a pupil imaging plane.

[0113] FIG5 schematically shows an optical path diagram of the second optical path of the small-aperture single-atom filter full-receiving optical path of the resonant fluorescence lidar according to an embodiment of the present disclosure.

[0114] As shown in Figure 5, the second optical path can include a fiber collimating lens group 2, a filter 3, a focusing lens 4, a polarization beam splitter prism 5, a focusing lens 71, a focusing lens 72, a focusing lens 73, a focusing lens 74, a plane mirror 75, a polarization beam splitter prism 8, a focusing lens group 9 and a detector photosensitive surface 1001.

[0115] According to an embodiment of the present disclosure, the layout of the second optical path is an L-shaped layout.

[0116] According to an embodiment of the present disclosure, the third position af11 is located near the focusing lens 72. The fourth position af12 is located near the focusing lens 73. The third position may be an imaging plane of the optical fiber end face, and the fourth position may be an imaging plane of the pupil af00.

[0117] FIG6 schematically shows a combined optical path diagram of the first optical path and the second optical path of the full-receiving optical path of the small-aperture single-atom filter of the resonant fluorescence lidar according to an embodiment of the present disclosure.

[0118] FIG7 schematically shows a combined structural diagram of the first optical path and the second optical path of the full-receiving optical path of the small-aperture single-atom filter of the resonant fluorescence lidar according to an embodiment of the present disclosure.

[0119] According to an embodiment of the present disclosure, the angle ag1 between the optical axis of the first optical path and the optical axis of the second optical path satisfies 0°≤ag1<3°, preferably 0°.

[0120] According to an embodiment of the present disclosure, the distance dx between the optical axis of the upper light path and the optical axis of the lower light path satisfies 5 mm < dx < 13 mm.

[0121] According to an embodiment of the present disclosure, as shown in FIG7 , d623 satisfies 25 mm < d623 < 150 mm, d634 satisfies 50 mm < d634 < 150 mm, and d645 satisfies 25 mm < d645 < 150 mm.

[0122] According to an embodiment of the present disclosure, d712 satisfies 25 mm < d712 < 150 mm, d723 satisfies 50 mm < d723 < 150 mm, and d734 satisfies 25 mm < d734 < 150 mm.

[0123] FIG8 schematically shows a structural diagram of a polarization beam splitter prism according to an embodiment of the present disclosure.

[0124] As shown in Figure 8, the polarizing beamsplitter prism consists of two right-angle prisms. One of the right-angle prisms has three sides z1, z2, and z3, three right-angle faces 01, 02, and 03, a side face 04, and an inclined face 05 coated with a polarizing beamsplitter film. The other right-angle prism is uncoated. Right-angle faces 01 and 03 can be coated with an anti-reflection coating.

[0125] FIG9 schematically shows a front view of a right-angle prism according to an embodiment of the present disclosure.

[0126] As shown in FIG9 , the right-angle prism angle b1 satisfies 30°<b1<70°, preferably 45°, and b2 is 90°.

[0127] FIG10 schematically shows a side view of a right-angle prism according to an embodiment of the present disclosure.

[0128] According to an embodiment of the present disclosure, the dimensions of the three sides of the right-angle prism: z1 satisfies 5mm<z1<12mm, z2 satisfies 5mm<z2<12mm, and z3 satisfies 5mm<z3<12mm.

[0129] According to an embodiment of the present disclosure, the wavelength of the incident light beam is any wavelength range from 200 nm to 3000 nm, d represents the center-to-center distance between the lens surfaces, and R represents the radius of curvature of each lens surface, where a positive value indicates that the curvature direction is toward the outgoing light direction, i.e., toward the right, and a negative value indicates that the curvature direction is toward the incident light direction, i.e., toward the left. Where n is the refractive index of the lens material at 587.6 nm, and v is the Abbe number of the lens material.

[0130] According to an embodiment of the present disclosure, the first optical path in Example 1 is shown in Table 1 below.

[0131] Table 1

[0132] According to an embodiment of the present disclosure, the second optical path in Example 1 is shown in Table 2 below.

[0133] Table 2

[0134] According to an embodiment of the present disclosure, the first optical path in Example 2 is shown in Table 3 below.

[0135] Table 3

[0136] According to an embodiment of the present disclosure, the second optical path in Example 2 is shown in Table 4 below.

[0137] Table 4

[0138] According to an embodiment of the present disclosure, the first optical path in Example 3 is shown in Table 5 below.

[0139] Table 5

[0140] According to an embodiment of the present disclosure, the second optical path in Example 3 is shown in Table 6 below.

[0141] Table 6

[0142] FIG11 schematically illustrates a detection method using a resonant fluorescence lidar small-aperture single-atom filter full-receiving optical path according to an embodiment of the present disclosure.

[0143] As shown in FIG11 , the above method includes operations S1101 to S1104 .

[0144] In operation S1101 , a light beam is collimated and converged by a front optical path component, and the light beam is split into a first light beam and a second light beam, wherein polarization directions of the first light beam and the second light beam are perpendicular to each other.

[0145] According to an embodiment of the present disclosure, a light beam from outside the full-receiving optical path of a small-aperture single-atom filter of a resonant fluorescence lidar can be received by a front optical path component and converged for output. The divergence angle of the collimated light beam is less than a first preset angle, and the divergence angle of the converged light beam is less than a second preset angle, wherein the first preset angle is less than the second preset angle.

[0146] According to an embodiment of the present disclosure, the converged light beam can be split into a first light beam and a second light beam with perpendicular polarization directions by the first polarization splitting component.

[0147] In operation S1102 , a first light beam is transmitted to a subsequent optical path component through a first optical path component in the polarization optical path components.

[0148] According to an embodiment of the present disclosure, the first light path formed by the first light path component passes through the atom cell to filter out noise light in the first light beam.

[0149] According to an embodiment of the present disclosure, the atom cell is used to filter out noise light in the first light beam.

[0150] In operation S1103 , the second light beam is transmitted to a subsequent optical path component through a second optical path component in the polarization optical path component.

[0151] According to an embodiment of the present disclosure, the second optical path formed by the second optical path component passes through the atomic cell to filter out noise light in the second light beam.

[0152] According to an embodiment of the present disclosure, the atom cell is used to filter out noise light in the second light beam.

[0153] In operation S1104 , the first light beam and the second light beam after the noise light is filtered out are simultaneously detected by a post-optical path component.

[0154] According to an embodiment of the present disclosure, the program code for executing the computer program provided by the embodiment of the present disclosure can be written in any combination of one or more programming languages. Specifically, these computer programs can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, languages ​​such as Java, C++, python, "C" or similar programming languages. The program code can be executed entirely on the user computing device, partially on the user device, partially on a remote computing device, or entirely on a remote computing device or server. In cases involving a remote computing device, the remote computing device can be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computing device (for example, using an Internet service provider to connect via the Internet).

[0155] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, program segment, or a part of code, and the above-mentioned module, program segment, or a part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0156] Those skilled in the art will appreciate that the features described in the various embodiments of the present disclosure may be combined and / or coupled in various ways, even if such combinations and / or couplings are not explicitly described in the present disclosure. In particular, the features described in the various embodiments of the present disclosure may be combined and / or coupled in various ways without departing from the spirit and teachings of the present disclosure. All such combinations and / or couplings fall within the scope of the present disclosure.

[0157] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above are only specific embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. A full-receiving optical path of a small-aperture single-atom filter for a resonance fluorescence lidar, comprising: A front optical path component for collimating and converging a beam and splitting the beam into a first beam and a second beam, wherein the polarization directions of the first beam and the second beam are perpendicular to each other, the divergence angle of the collimated beam is less than a first preset angle, and the divergence angle of the converged beam is less than a second preset angle, and the first preset angle is less than the second preset angle; A polarization optical path component comprising a first optical path component and a second optical path component, The first optical path component for transmitting the first beam to a rear optical path component, wherein the first optical path formed by the first optical path component passes through an atomic cell to filter out the noise light in the first beam; The second optical path component for transmitting the second beam to a rear optical path component, wherein the second optical path formed by the second optical path component passes through the atomic cell to filter out the noise light in the second beam; A rear optical path component for simultaneously detecting the first beam and the second beam after filtering out the noise light.

2. The full-receiving optical path of a small-aperture single-atom filter for a resonance fluorescence lidar according to claim 1, wherein, When the first beam enters the atomic cell, the divergence angle of the first beam is less than a third preset angle, and the third preset angle is greater than the second preset angle; When the second beam enters the atomic cell, the divergence angle of the second beam is less than the third preset angle.

3. The full-receiving optical path of a small-aperture single-atom filter for a resonance fluorescence lidar according to claim 1, wherein, The first optical path component and the second optical path component are distributed on the upper and lower sides of the central axis of the full-receiving optical path of the small-aperture single-atom filter for a resonance fluorescence lidar, and the optical axis of the first optical path formed by the first optical path component does not intersect with the optical axis of the second optical path formed by the second optical path component; The distance between the component edge of the first optical path component away from the central axis and the component edge of the second optical path component away from the central axis is less than 22 mm.

4. The full-receiving optical path of a small-aperture single-atom filter for a resonance fluorescence lidar according to claim 1, wherein, The first beam and the second beam are controlled according to the same control parameters at the atomic cell.

5. The full-receiving optical path of a small-aperture single-atom filter for a resonance fluorescence lidar according to claim 1, wherein, The optical path length of the first optical path is equal to the optical path length of the second optical path, so that the first beam and the second beam reach the rear optical path component simultaneously.

6. The full-receiving optical path of a small-aperture single-atom filter for a resonance fluorescence lidar according to claim 1, wherein, The rear optical path component includes: A first polarization beam splitter for combining the first beam and the second beam after filtering out the noise light into a third beam; A focusing lens group for converging the third beam into a fourth beam; A detector disposed after the focusing lens group for detecting the fourth beam; Wherein, the focusing lens group is used to image and converge the pupil of the fourth light beam onto the photosensitive detection surface of the detector; the width of the photosensitive detection surface is smaller than the width of the focusing lens group.

7. The full receiving optical path of the small-aperture single-atom filter of the resonance fluorescence lidar according to claim 1, Wherein, The preposed optical path assembly includes: An optical fiber for receiving the light beam; An optical fiber collimating lens group disposed after the optical fiber and used to collimate the light beam output from the optical fiber. Wherein, the divergence angle of the light beam output by the optical fiber collimating lens group is smaller than the first preset angle; A first focusing lens disposed after the optical fiber collimating lens group and used to converge the collimated light beam to obtain a converged light beam. Wherein, the divergence angle of the light beam output by the first focusing lens is smaller than the second preset angle; A second polarization beam splitter disposed after the first focusing lens and used to split the light beam into the first light beam and the second light beam.

8. The full receiving optical path of the small-aperture single-atom filter of the resonance fluorescence lidar according to claim 1, Wherein, The first optical path assembly includes: A first reflector for changing the direction of the first light beam; A second focusing lens disposed after the first reflector and used to image the fiber end face of the first light beam to a first position; A third focusing lens disposed between the second focusing lens and the atomic cell. The third focusing lens serves as a field lens and is used to input the first light beam into the atomic cell. Wherein, the first position is located between the second focusing lens and the third focusing lens; A fourth focusing lens disposed after the atomic cell and used to converge the first light beam output from the atomic cell; A fifth focusing lens disposed after the fourth focusing lens and used to converge and image the fiber end face; Wherein, the second focusing lens and the third focusing lens are paired to jointly image the pupil of the first light beam to a second position, and the second position is located between the atomic cell and the fifth focusing lens.

9. The full receiving optical path of the small-aperture single-atom filter of the resonance fluorescence lidar according to claim 1, Wherein, The second optical path assembly includes: A sixth focusing lens for imaging the fiber end face of the second light beam to a third position; A seventh focusing lens disposed between the sixth focusing lens and the atomic cell. The seventh focusing lens serves as a field lens and is used to input the second light beam into the atomic cell; Wherein, the third position is located between the seventh focusing lens and the atomic cell; An eighth focusing lens for converging the second light beam output from the small-aperture single-atom filter of the resonance fluorescence lidar; A ninth focusing lens disposed after the eighth focusing lens and used to converge and image the fiber end face; Wherein, the sixth focusing lens and the seventh focusing lens are paired to jointly image the pupil of the second light beam to a fourth position, and the fourth position is located between the atomic cell and the ninth focusing lens; A second reflector, disposed behind the ninth focusing lens, for reflecting the second light beam collimated by the ninth focusing lens to the rear optical path assembly.

10. A detection method for a small-aperture single-atom filter full-reception optical path of a resonance fluorescence lidar using any one of claims 1 to 9, comprising: collimating and converging a light beam through a front optical path assembly, and splitting the light beam into a first light beam and a second light beam, the polarization directions of the first light beam and the second light beam being perpendicular to each other, the divergence angle of the collimated light beam being less than a first preset angle, and the divergence angle of the converged light beam being less than a second preset angle, the first preset angle being less than the second preset angle; transmitting the first light beam to the rear optical path assembly through a first optical path assembly in the polarization optical path assembly, wherein the first optical path formed by the first optical path assembly passes through an atomic cell to filter out noise light in the first light beam; transmitting the second light beam to the rear optical path assembly through a second optical path assembly in the polarization optical path assembly, wherein the second optical path formed by the second optical path assembly passes through the atomic cell to filter out noise light in the second light beam; simultaneously detecting the first light beam and the second light beam after filtering out noise light through the rear optical path assembly.

Images